1. Field of the Invention
The present invention relates to a wire harness for use in an automobile or the like.
2. Description of the Related Art
A wire harness has been used for a wiring arranged in an automobile. The wire harness is also referred to as assembled electric wires, which are formed in such a manner that a plurality of electric wires are assembled in advance into one body so that the electric wires can be formed into a shape necessary for wiring. As shown in FIG. 1, after necessary branches have been formed in the wire harness and necessary connectors have been attached to the end portions of the wire harness, a tape is wound around the bundle of electric wires. PVC insulating electric wires have been used for the electric wires, and PVC tapes having an adhesive have been widely used for the tapes.
The wire harness as described above is used for air planes and electric appliances , such as video tape players.
Concerning the PVC insulating electric wires which have been widely used as insulating electric wires, it has recently become necessary to make investigation into a substitute so that the environmental problems can be solved.
As a substitute for PVC insulating electric wires, it has been proposed to use insulating electric wires made of non-halogen fire-resistant polyolefine in which a large quantity of inorganic filler is added to polyolefine.
According to the thus made investigation, it has become necessary to reinvestigate PVC tapes used for the wire harness.
Even after the PVC tapes are assembled into the wire harness, it is necessary that the PVC tapes have a fire-resistance property. If it is possible to use tapes made of non-halogen fire-resistant polyolefine which are recommended as the wire harness tapes, any problems would not be caused. However, in order to enhance the fire-resistance property, a large quantity of inorganic filler has to be added to non-halogen fire-resistant polyolefine. Therefore, it is very difficult to make thin tapes of non-halogen fire-resistant polyolefine, and further the manufacturing costs of the tapes are raised in such a case.
The present inventors have found that, even if combustible material is used for a tape, as long as the tape is made thin and elongated, it can be judged to be self-extinguishable in a combustion test stipulated in JIS C3005 after the tape is assembled into a wire harness. The present invention has been accomplished on the basis of the above knowledge.
According to the present invention, there is provided a wire harness including a bundle of electric wires round which an adhesive tape made of resin composition, the principal component of which is polyolefine, the coefficient of heat-contraction against adhesion at 180xc2x0 C. of which is not less than 30%, is wound.
According to the present invention, there is provided a wire harness in which the maximum value of the width of an opening on the tape is not less than one third of the entire circumference of the portion concerned of the wire harness when the wire harness is heated.